She began her flag project in 1908 as part of her volunteer activities with the Daughters of the American Revolution (DAR) when she was appointed chairperson of the DAR committee to research and design Missouri's flag. Oliver researched state flags extensively. She wrote each state's secretary of state for information about how their state's flags had been designed and officially adopted. Her original design incorporated Missouri's coat of arms and was rendered as a painted paper flag by her friend Mary Kochitzky.The flag consists of three horizontal stripes of red, white and blue. These represent valor, purity, vigilance, and justice. The colors also reflect the state's historic status as part of the French Louisiana (New France). In the center white stripe is the Seal of Missouri, circled by a blue band containing 24 stars, symbolizing Missouri's admission as the 24th U.S. state.Except for the Seal of Missouri in its middle, the flag is identical with the Flag of the Netherlands; this resemblance is not, however, intended to denote any special relation between Missouri and the Netherlands.